從 python 中的字符串中過濾正負詞

Question

我有一個帶有 boolean 邏輯表示的字符串，我想從中提取正面和負面的詞。 否定詞是前面有not的詞。

示例 1 -

Input - 

(A and B and C) and not (E or F)

Output - 

positive - A & B & C
nagative - E | F

示例 2 -

(A and B) and not E and C

Output - 

positive - A & B & C
nagative - E

我想我可以通過拉平繩子來做到這一點，例如 -

(A and B and C) and not (E or F)變成A and B and C and not E or not F然后使用正則表達式提取正負詞，但不知道該怎么做。

最好的方法是什么？

Answer 1

對於無法提供通用解決方案，我深表歉意。 在制定解決方案時，我做了以下假設：

1. 沒有大括號的層次結構，例如， A and (B and (C or (D and E)))是不允許的。
2. 最低級別的連接運算符是'and'，例如， (something) and (something) and...

代碼：

import regex

def get_positive_and_negative_statements(logical_string):
    output = dict()
    positives = regex.findall(r"(?<!not\s+)(\((?:[A-Z]+\s+(?:and|or)\s+)+[A-Z]+\)|(?<!\([^\)]*)[A-Z]+)", logical_string)
    output["positive"] = " & ".join([element.replace(" and ", " & ").replace(" or ", " | ") for element in positives])
    negatives = regex.findall(r"(?<=not\s+)(\((?:[A-Z]+\s+(?:and|or)\s+)+[A-Z]+\)|(?<!\([^\)]*)[A-Z]+)", logical_string)
    output["negative"] = " & ".join([element.replace(" and ", " & ").replace(" or ", " | ") for element in negatives])
    return output

str1 = "(A and B and C) and not (E or F)"
str2 = "(A and B) and not E and C"
output1 = get_positive_and_negative_statements(str1)
output2 = get_positive_and_negative_statements(str2)

print(f"In {str1} ---\n{output1}")
print(f"\nIn {str2} ---\n{output2}")

Output：

In (A and B and C) and not (E or F) ---
{'positive': '(A & B & C)', 'negative': '(E | F)'}

In (A and B) and not E and C ---
{'positive': '(A & B) & C', 'negative': 'E'}